在 XNA 中更改旋转矩阵的原点

Question

我试图得到4个Vector2对象，它们代表一个精灵的4个角，在精灵自身围绕其中心旋转时旋转。但是，在下面的代码中，Vector2对象在客户端空间中围绕0,0旋转，而不是围绕对象的中心旋转。使用矩阵变换，是否有任何方法可以围绕对象的中心而不是全局坐标（0,0）旋转Vector2对象？

这是迄今为止旋转的函数：

public Vector2[] CheckCollision()
    {
        //Get the 4 corners of the sprite locally
        //We can get all 4 corners from only 2 vectors
        Vector2 topLeft = new Vector2(position.X - spriteSize.X, position.Y - spriteSize.Y);

        //Not sure why position is representing the
        //bottom right instead of the center here....
        Vector2 bottomRight = position;

        Vector2 bottomLeft = new Vector2(topLeft.X, bottomRight.Y);

        Vector2 topRight = new Vector2(bottomRight.X, topLeft.Y);

        //Create transformation matrix
        Matrix transform = Matrix.CreateRotationZ(MathHelper.ToRadians(this.direction)) *
            Matrix.CreateScale(this.scale);

        //Transform the vectors
        topLeft = Vector2.Transform(topLeft, transform);
        bottomRight = Vector2.Transform(bottomRight, transform);
        bottomLeft = Vector2.Transform(bottomLeft, transform);
        topRight = Vector2.Transform(topRight, transform);

        Vector2[] vectorArray = new Vector2[4];

        vectorArray[0] = topLeft;
        vectorArray[1] = bottomRight;
        vectorArray[2] = bottomLeft;
        vectorArray[3] = topRight;

        return vectorArray;

    }

Answer 1

在添加spritePotion之前先旋转四个角并在执行旋转和缩放后添加spritepost可能会容易得多。

把你的四个角做成相应的< code>spriteSize组合，做< code>Vector2。Transform完成后，将< code>spritePosition添加到< code>vectorArray中的四个向量